Magnetic catch



Dec. 6, 1955 M. o. TEETOR MAGNETIC CATCH Filed 001'.. 8, 1954 55 I i?Le?.

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United States Patent MAGNETIC CATCH Macy 0. Teetor, New Orleans, La.,assigner to T-K Corn poration, New Orleans, La., a col-'porationV ofLouisiana ppiication ctober 8, 1954, SerialNo. 461,269 6 Claims. (Cl.292-2515) This invention relates to a novel magnetic catch for retaininga closure member, such as a cabinet door, in closed position adjacent aframe member. More particularly, the invention relates to a novelmagnetic catch for use on double doors.

Magnetic door catches of various types'have been suggested heretofore inwhich the cooperating magnet and armature units are mounted in coactingpositions on door and frame members. In my prior Patents Nos. 2,508,305and 2,690,348 I have described a highly effective type of magnetic catchwhich affords several important advantages not previously available' inthe magnetic catch art. One important feature of my prior inventioninvolves the movable mounting" of one of the catch elements, e. g; themagnetelement, incombination with a spring member operatively coactingwith the movable catch element for normally urging the latter intoretracted position relative to the supporting door or frame member. Bymeans of such arrangement, the catch readily compensates for relativemisalignment between the door and frame members so that full surfacecontact between the catchv elements is obtained.

The present invention is directed to a novel adaptation of a magneticcatch of the foregoing type which is particularly suited for use withdouble doors. In a double door cabinet it might be supposed that aseparate armature element could be provided on each door and that asingle movable magnet` unit could then be mounted on the cabinet frameso as to span the space between the free edges of the hinged doors andextendinto operative relation with both of the armature elements on thedouble doors. Howevenl have found that the solution is not quite sosimple. In the' first place, the armature on the rst door to be closedcor'npletes the magnetic circuit with the magnet so that the' magnetthen has a substantially reduced attraction for the armature on thesecond door. Consequently, at any given time an enicient closing actionis provided for only one of the doors. For the same reasons, when bothdoors are closed the first door to be opened requiies too little forceor pull whereas only the remaining door has proper resistance to openingpull.

However, an even greater difficulty is encountered because of theself-aligning characteristics of the magnet element as described morekfullyv in my aforementioned Patents Nos. 2,508,305 and 2,690,348. Whenthe first door is closed, the spring mounted-- magnet automaticallyaligns itself with the armature on the first door` so that full surfacecontact is obtained therebetween. However, it is extremely unlikely thatthe face of the second door when closed will be in exact coplanaralignment with the rst door. Since the magnet has already made thenecessaryadjustment with the iirs't door, thisy relationship will beretained and when the second door is closed its armature willnecessarily make o 'nly incomplete line or point contact with the magnetso that the last door to be' closed is held only ine'i'r'ectively atbestbe'c'ause of' the" reduced magnetic contact area.

Patented Dec. 6, 195.5

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Accordingly, a primary object of the present invention is to overcomesuch difficulties and provide a novel and effective magnetic catcharrangement for double doors which utilizes only a single magnet unitfor both doors.

A further object of the invention is to provide a simplified magneticcatch mechanism for use on double doors which permits equally effectiveclosing and opening of both doors.

Another object of the invention is to provide a novel magnetic catchdevice for use on double doors which utilizes only a single magnet unitbut at the same time compensates for relative misalignment between thetwo doors and between the doors and their supporting frame.

Other objects and advantages of the invention will become evident fromthe subsequent detailed description taken in conjunction with theaccompanying drawing, wherein:

Pig. l is a fragmentary front elevational View of the lower portion of adouble door cabinet in closed position and having mounted thereon amagnetic catch embodying the principles of the invention;

Fig. 2 is an enlarged front elevational View of the magnet unit of thecatch as seen with the cabinet doors open;

Fig. 3 is an enlarged vertical sectional view as taken along the line 33 of Fig. l;

Fig. 4 is an enlarged horizontal sectional view as taken along the line4 4 of Fig. l; and

Fig. 5 is a View similar to Fig. 4 but showing the manner in which thecatch compensates for misalignment between the two doors.

Referring first to Fig. l of the drawing, a cabinet is shown comprisinga pair of double doors 11 and 12 having hinged mountings 13 at theiropposite edges on the upright side portions 14 of the cabinet frame. Theadjacent free edges of the doors 11 and 12 are spaced a. slight distanceapart in the usual manner, as indicated at 16. The cabinet is providedwith a magnetic catch embodying the features of my invention andconsisting of a magnet unit 17 mounted centrally on the base portion 18of the cabinet frame and a pair of cooperation armature units 19 (Figs.3, 4, and 5) affixed to the inner faces of the doors 11 and 12. Themagnet unit and the two armature units are thus mounted in coactingpositions on the cabinet frame and doors, respectively, so that eitheror both of the armature units 19 is in operative engagement with themagnet unit 17 when either or both of the cabinet doors are in closedposition against the frame. It should be understood that the cooperatingmagnet and armature units may be mounted in any desired co'acting`positions on the door and cabinet structure as long as the magnet unit17 is so mounted as to coact with both of the armature units 19. Forexample, the catch units may be aiXed adjacent the upper portion of thecabinet frame and doors or adjacent an intermediate shelf por tion ofthe cabinet instead of at the base of the cabinet as shown'in Fig. 1.

Referring now to Figs. 2 to 4, the magnet unit 17 of thedevice comprisesan elongated magnet housing or body portion, indicated generally at 21,having a mounting ftange 22 along one longitudinal side thereof, acentrally located cup-shaped recess or socket portion 2.3 extendinginwardly from the front of the housing for receiving the magnet means,and a pair of forwardly extending anges or abutments 24 at the front ofthe housing adapted to protect the magnet means from direct strikingimpact with the armature units, as hereinafter described in detail. Thehousing 21 is rigidly affixed to the cabinet frame, in this instance tothe base portion 18 thereof, by means of a pair of screws 27e-extendingthrough a pair of edgewise slots or openings 27 in the mounting flangeZ2. The openings 27 extend inwardly a substantial distance from 3 therear edge of the flange 22 to permit the magnet unit 17 to be adjustedto proper position adjacent the edge of the cabinet frame when beingmounted.

The magnet housing 21 is formed from an appropriate non-magneticmaterial such as brass, zinc, aluminum or a suitable plastic material. Apair of generally U-shaped complementary magnet elements 28 and 29 aredisposed loosely within the socket or recess 23, the latter being openand unobstructed at the front of the housing 21. In this case, themagnet-receiving socket or recess 23 has a generally rectangularconfiguration with rounded corner portions, and the magnet elements 28and 29 are shaped accordingly to conform to the configuration of thesocket portion 23. The magnet elements 28 and 29 are formed from amagnetic metal or alloy, particularly the highly eective alloy ofaluminum, nickel, and cobalt known commercially as Alnico Because of thegenerally U-shaped or channel-shaped form of the magnet elements 28 and29, these may conveniently be manufactured from an elongated eastchannel-shaped bar of magnetic metal or alloy which is then cut intosections of suitable size. These sections may then be ground to providethe desired external contiguration complementing the inner configurationof the socket 23. On the other hand, it is also possible to utilizeavailable pre-cast or preformed magnet elements of a relatively largersize merely by cutting the magnet elements in half to provide thecoacting elements 28 and 29. In either event, the magnetization of theelements 28 and 29 is very important for the purposes of the presentinvention. Briefly, I have found that for proper operation it isnecessary that the mutually adjacent pole portions or legs of therespective magnet elements 28 and 29 have a like polarity so that themagnet units 28 and 29 repel each other and are normally spaced apartwithin the socket 23, as indicated at 31 (Fig. 2). The desired magneticcondition is indicated by means of plus and minus signs in Fig. 2 sothat it will be evident that the pole portions of the respectiveelements 28 and 29 at opposite sides of the catch are similar or havelike polarity. Thus, there is a mutual magnetic repulsion between theadjacent pole portions or legs of the respective magnet elements.

As described earlier, I have found that the catch becomes ineffectivefor double door operation if only a single magnet element is employed tocoact with two separate armature elements on the respective doors of thecabinet. For exactly the same reasons, even the pair of magnet elements28 and 29 will be ineffective unless the magnetic poles of therespective magnet elements are oriented in mutually repellent relationas shown in Fig. 2. For example, if the polarity or magnetizationbetween the leg portions of each of the elements 28 and 29 were reversedfrom the condition shown in Fig. 2, it will be evident that there wouldthen be a strong attraction between the two magnet elements 28 and 29 sothat they would adhere together and function as a unit in exactly thesame manner as if only a single large magnet element were employed.Consequently, the important principle of my invention is to utilize asingle magnet housing containing two independent magnet elements whichare so magnetized as to be mutually repellent whereby the magnetelements are normally maintained in spaced apart and independentlymovable relation.

In addition to the space 31 between the mutually repelled magnetelements 28 and 29, it will also be seen that the dimensions of themagnet elements are suiciently restricted as compared with the size ofthe socket 23 to provide a slight clearance 32 at the front and rearsides of the magnet unit. Thus, when required, each of the magnetelements 28 and 29 can automatically assume a limited angular or cockedposition relative to the stationary socket 23 in order to accommodatestructural misalignments, as hereinafter described in connection withFig. 5. The base of the socket portion 23 at the rear of the catch isprovided with a dome-shaped bump or projection 33 (Fig. 3) upon whichthe magnet elements 28 and 29 rest when in retracted position within thesocket, and the depth of the socket 23 is such as to permit the fullaxial height of the magnet elements 28 and 29 to be fully enclosed bythe socket 23 and to be protected when in normal retracted position.

As previously described, the magnet elements 28 and 29 are generallyU-shaped so as to provide a central groove 34 in each of the magnetelements in the manner of a horse-shoe type magnet. An elongated barspring 36, formed from a suitable resilient and non-magnetic springmaterial such as a strip of phosphorus-bronze spring metal, is disposedlengthwise within the housing 21 and extends through the aligned magnetgroove 34. The end walls of the magnet-receiving socket portion 23 arecut away or open, as shown at 37 in Fig. 4, so that the ends of the barspring 36 extend beyond the socket portion 23 and are seated against orengaged behind a pair of upright front walls or shoulder portions 38 atthe front of the housing. As will be evident from the drawing, theintermediate portion of the bar spring 36 which is contained within thesocket portion 23 directly engages the magnet elements 28 and 29 at thebase portions of the grooves 34 therein and the magnet elements arethereby normally retained in a retracted position (not shown) in contactwith the projection 33 at the bottom of the socket 23. Consequently, itwill be seen that the intermediate portion of the spring 36 is free tomove transversely relative to the elongated housing 21 therebypermitting outward resilient movement of the magnets 28 and 29 in thedirection of and through the open front portion of the socket 23.

The armature units 19 comprise in this case a pair of flat metal platesformed from a magnetic metal such as iron or steel and secured to theinner faces of the doors 11 and 12 adjacent the free edges thereof bymeans of screws (not shown) or the like. Of course, the dimensions ofthe armature plates 19 are sufiicient to fully accommodate the outercontact faces of the respective magnet elements 28 and 29. As will bereadily understood, the strength of the magnetic attraction between themagnet elements 28 and 29 and their respective armatures 19 is greaterthan the tension exerted by the spring 36 tending to hold the magnets inretracted position. Thus, outward movement of the magnet elements 28 and29 into engagement with the armatures 19 on the doors is readilypermitted when the doors are closed as seen in Figs. 3 and 4. However,it will also be understood that when either or both of the doors 11 and12 are in open position away from the cabinet frame, the magnetic forcesbetween the magnet elements and their respective armatures is disruptedso that the spring 36 retracts one or both of the magnet elements intothe socket portion 23. By reason of the fact that the magnet elements 28and 29 are repelled into spaced-apart relation by magnetic repulsiveforces, it will be seen that the two magnet elements 28 and 29 althoughcontained within a single unitary housing are free to act independentlyof each other to a large extent. Thus, if door 11 is closed first, themagnet element 28 moves out` wardly in resilient fashion against thetension of spring 36 and engages the armature 19 on the door 11 so thatthe latter is held securely in closed position by the action of thespring 36. However, since the magnet 29 is repelled in spaced apartrelation from the magnet element 28, the closure of the door 11 does notexert any detrimental eiect on the magnetic attraction exerted by themagnet element 29 and, of equal importance, the magnet element 29 isunaffected by any angular or cocking movement of the magnet 28 whichautomatically takes place to effect full surface contact between themagnet element 28 and its armature 19. When the door 12 is closedthereafter, the magnet element 29 exerts full magnetic attraction fory te-arna't'il're, 1:9ioii' tli' dr 12 and is self-aligning therewith asrequired. I y

The independent self-adjustability ofthe tiv magnet elements 28 and 29as described above isA more fully illustrated in Fig. 5. As shown`therein, thel door 11 is warped or bulged to4 a slightl extent and failsto align itself properly with the base 18 ofY the cabinetfratrie.However, because of its loose resilient rr'iuntirgA as Hereinbeforedescribed, the magnet 28 undergoes angular or twisting movement as shownin Fig. 5 whereby to permit full surface flat-wise engagement betweenthe outer ends of the magnet poles and the corresponding armature plate19 on the door 11. It will be understood that a similar angular orcocking movement can likewise occur when necessary to compensate formisalignment in a vertical plane. At the same time, because of themagnetic repellent forces which are exerted between the magnet elements28 and 29, the angular twisting of the magnet 28 as shown in Fig. 5 doesnot exert any detrimental effect on the magnet 29. Accordingly, themagnet 29 is free to align itself as required for full surfaceengagement with the armature plate 19 on the door 12. In other words,the magnet elements 28 and 29 have substantially independentself-aligning characteristics so as to accommodate any misalignmentwhich may ordinarily be encountered between the door 11 and the cabinetframe or between the door 12 and the cabinet frame or both. In thesituation illustrated in Fig. 5, the door 11 is out of alignment withthe cabinet frame but the door 12 is shown in substantially exactalignment. Obviously, if only a single magnet element were used or ifthe magnet element 29 were eiected by the aligning movement of themagnet 28, then only the first door to be closed would have properholding engagement between the magnet and armature elements and tosecond door to be closed would have only restricted ineffective magneticcontact between the catch elements.

It should also be mentioned that in mounting the magnet unit housing 21in the cabinet frame, the forwardly projecting anges or abutments 24 areallowed to extend beyond the supporting surface such as the base 1S onthe cabinet frame. This arrangement accomplishes a two-fold purpose.First of all, the doors when closed abut against the flanges 24 (as seenin Figs. 3 and 4) so that the armature 19 is necessarily held outwardlyin spaced relation from the magnet housing 21 and as a result the magnetelements 28 and 29 must move outwardly under magnetic attraction toengage the armature elements thereby placing the spring 36 under tensionand insuring the desired resilient retention of the doors in closedposition by the spring action. Another purpose of the ilanges 24 is toprotect the relatively brittle magnet elements 28 and 29 from severedirect striking impact with the armatures 19 when the doors are forciblyclosed. In other respects, the operation of the catch of the presentinvention is similar to the arrangement described in my previouslymentioned prior pat ents, particularly Patent No. 2,690,348.

Although the invention has been described with particular reference to acertain specic structural embodiment thereof, it will be understood thatvarious modiications and equivalent structures may be resorted towithout departing from the scope of the invention as defined in theappended claims.

I claim:

l. A magnetic catch for holding double doors in closed position adjacenta frame, said catch comprising a nonmagnetic housing, a pair of magnetelements each having dissimilar pole portions and loosely disposed insaid housing, said magnet elements being arranged side-byside in saidhousing with the similar pole portions of the respective magnet elementsdisposed in adjacent mutually repellent relation whereby said magnetelements are normally urged to spaced-apart position within saidhousing, said housing being mountable on the frame centrally df! thedehntdoers; resin-fit` means nermauy urging the lagnet elements inwardlyof said housing, and a pair of' coacting armature elementsvadap'ted' tobe secui'd to said doors for coaction with said magnet ele'- mentsf,each of thelmagneit elements being movable out'- wardly toward andselectively self-ali'gnable' with its resp'ective' armature element. y A

2. 1liV a magnetic catch', a l'ignt unit adapted t be mounted on a framefor coaction with a pair of double doors each having its own armatureelement, said magnet unit comprising a non-magnetic housing rigidlysecurable to the frame and having a magnet-receiving recess, a pair ofmagnet elements loosely and movably disposed in said recess, each ofsaid magnet elements having a pair of spaced forwardly-extending polesof opposite polarity with the like and unlike poles of the respectivemagnet elements being oriented in side-by-side mutually repellentrelation whereby said magnet elements are normally urged to spaced-apartposition within said recess, and resilient means for normally urging themagnet elements into retracted position in said recess, said resilientmeans permitting forward movement of the magnet elements into contactwith the armature elements on the doors and each of the magnet elementsbeing individually alignable with its respective armature element.

3. In a magnetic catch, a magnet unit adapted to be mounted on a framefor coaction with a pair of double doors each having its own armatureelement, said magnet unit comprising a non-magnetic housing rigidlysecurable to the frame and having a magnet-receiving recess, a pair ofmagnet elements loosely and movably disposed in said recess, each ofsaid magnet elements having a pair of spaced forwardly-extending polesof opposite polarity with the like and unlike poles of the respectivemagnet elements being oriented in side-by-side mutually repellentrelation whereby said magnet elements are normally urged to spaced-apartposition within said recess, and an elongated bar spring disposed insaid housing and extending between the poles of the magnet elements andresiliently engaging the latter for normally urging the magnet elementsinto retracted position in said recess, said magnet elements beingmovable forwardly under magnetic attraction against the action of saidspring into contact with the armature elements on the doors and each ofthe magnet elements being selectively alignable with its respectivearmature element.

4. The structure of claim 3 further characterized in that said magnetelements are generally U-shaped elements with the spaced legs thereofcomprising the poles of the magnets and the like poles of one polarityof the respective magnet elements are at one side of said spring and thelike poles of opposite polarity are at the other side of said spring.

5. A magnetic catch for a pair of doors hingedly mounted on a frame withthe free edges of the doors in slightly spaced relation when the doorsare closed, said catch comprising unitary housing structure mountable onthe frame and adapted to extend across the space between the free edgesof the doors, a pair of movable magnet elements loosely disposed in saidhousing structure and arranged in magnetically repelled relation forindependent movement, unitary resilient means coacting with the housingstructure and both of said magnet elements for normally urging thelatter into retracted position within the housing structure, and a pairof armature elements mountable on the doors in coacting relation withsaid magnet elements, said magnet elements being movable outwardly undermagnetic attraction against the action of said resilient means intocontact with said armature elements and being rockable separately forindependent alignment with the armature elements.

6. In combination, a frame, a pair of hinged doors on said frame, amagnet unit mounted on the frame and overlying both of said doors whenthe latter are closed, and a pair of separate armature elements mountedon said 2,726,110 7 8 doors in operative relation with said magnet unitwhereby operable with one of said magnet elements and said the singlemagnet unit serves to hold both doors closed, magnet elements beingmovable outwardly and individualsaid magnet unit comprising anon-magnetic housing 1y alignable for full surface contact with therespective rigidly fastened to the frame, a pair of magnet elementsarmature elements.

loosely contained Within said housing in mutually repel- 5 lent relationwhereby said magnet elements are normally References Cited in the fileof this patent spaced-aoart within said housing, and means resilientlyUNITED STATES PATENTS urging said magnet elements mto retracted positlonw1thm 2,489,154 Renon Nov. 22 1949 Said housing, each of sald armatureelements being co- 2169013 48 ,rector Sept' 28, 1954

